Gel filtration of Sephadex G-75 column chromatography revealed aging effects that occurred in the low molecular weight proteins of human lenses. In the older lens heavy molecular weight gamma crystallin (M.W. 24,000) and beta-s crystallin (M.W. 28,000) increased, while the light molecular weight gamma crystallin (M.W. 20,000) decreased. The aging changes observed in the low molecular weight proteins of human lens are generally similar to those observed in the bovine lenses. However analyses of ionic exchange SP-Sephadex column chromatography, poly-acrylamide gel electrophoresis with and without sodium dodecyl sulfate (SDS) revealed that one of the shoulder peaks of light molecular weight human gamma crystallin showed a molecular weight of 11,000 which was an unexpected results in normal human lens. This smallest size gamma crystallin possessed very similar immunological cross reactivity with other major human gamma crystallins. Moreover analyses of amino acid composition, N-terminal amino acid, amide content and immunodiffusion studies have further characterized the low molecular weight proteins in the human lens.